The present invention concerns elements for making a protective reactive armor to be fitted on the outside of an enclosure liable to be exposed to attack by shaped-charge warheads and kinetic energy projectiles. Examples of enclosures protectable by a reactive armor made of elements according to the invention are armored land vehicles such as battle tanks, armored personnel carriers, armored fighting vehicles, armored, self-propelled guns and the like; armored marine vessels; armored static structures such as buildings, above-ground portions of bunkers, container tanks for the storage of fuel and chemicals and the like; etc. A reactive armor element according to the invention may be a basic type armor made integral with a conventional passive armor element, or alternatively of the add-on type.
Warheads with shaped-charge munition, also known as hollow charge munition, are known to pierce armor and thereby destroy from within objects located inside an armored enclosure. This capacity of a shaped charge results from the fact that upon detonation there forms an energy-rich jet also known as "thorn" or "spike" which advances at very high speed of several thousand meters per second and is thereby capable of piercing even relatively thick armor walls.
In U.S. Pat. No. 4,368,660 there is described an arrangement which purports to afford protection against the penetrating effect of an exploding shaped charge. According to that proposal there is provided a continuous wall structure having an explosive layer sandwiched between two wall members of an inert material, e.g. a metal, and being so arranged that the axis of an impinging projectile and of the jet formed upon detonation, includes with the surface of the wall structure an acute angle of say 45.degree.. According to said U.S. patent, when a jet of a hollow charge projectile penetrates the upper surface of such a protective arrangement it initiates the explosive layer and in consequence the walls thereof are thrown apart in opposite directions, both essentially normal to their surfaces. Thus one of the wall members moves in the direction of the protected substrate while the other moves away and in consequence and due to the acute angle included between the jet and the wall member surfaces, the jet is successively intersected by different portions of the moving wall members with the consequence that the mass and energy of the jet are rapidly consumed whereby the jet is attenuated.
A similar arrangement is disclosed in GB-A-1,581,125 with the sole difference that in accordance with that disclosure the arrangement of the layer of explosive substance may optionally be covered only on one side by a layer of a non-combustible material.
An improved protective armor is disclosed by the present Applicants in their U.S. Pat. No. 4,741,244 and the corresponding EP-B1-0 161,390. This improved protective armor is of the add-on type and consists of a plurality of elements each comprising a cover member having suspended therefrom on the side that faces the substrate at least one explosive insert comprising an explosive layer sandwiched between two metal plates such that when the element is mounted on a substrate the explosive insert remains distant therefrom.
Prior art reactive armors have the drawback that due to the intrinsic inertia of the reactive system and the high velocity of the jet head, a front portion of an oncoming jet manages to penetrate and reach the main armor practically without any attenuation, and although such a head portion accounts only for a fraction of the energy and mass liberated by a shaped detonating charge, it is nevertheless liable to cause damage. A further drawback of known reactive armors of the kind specified is due to the fact that in operation the innermost metal plate of the two plates between which the explosive charge is sandwiched, i.e. that plate that is closest to the main, passive armor, is hurled against the latter and the resulting impact may cause internal damage such as spalls and mechanical deformation, and also undesired shocks and vibration. In case of deformation of the inner side of a wall portion in an armored vehicle, operative parts such as the engine, the communication system, the weaponry and the like are liable to be damaged. Similar damage is liable to occur in consequence of spalling in which case, moreover, personnel is liable to be injured by inwardly hurled spalls and hydraulic, electric and fuel systems are liable to be damaged.